Hmmm.... Austen's world was patriarchial: females could not own property (though there were a few legal ways around that) and there were very few occupations available to gentlewomen (governess, companion). As a result, a female was entirely dependent on her father or guardian, and then later on her husband, to see to the family's financial well-being. Austen's Mr. Bennet does not do this-- he does not curb his wife's spending, nor does he put aside money each year as savings-- not due to any lack of intelligence, but due to a lack of initative. These are clearly written as character flaws, as Mr. Bennet's character is written as a foil for Mr. Darcy (who is attentive to his estate management, supervises his sister's education closely, maintains correspondence with his sister and business, etc.). This allowed Austen to show the evolution of Elizabeth's character: at the beginning of the story, she favors a man with a ready wit (Wickham) that he uses to amuse her by jeering at acquaintances, but by the end of the story, she chooses to marry (and thus submit herself to the authority of) a man very unlike her father-- a man who is not glib nor particularly witty, but who can be relied on to fulfill his responsibilities to the best of his ability.
Also, I don't think Austen's Mrs. Bennet is quite as clueless as she is often presented in film and fanfiction. She recognizes that her husband's wit can be used in protection of their family: for example, when she and the girls return from the Meryton assembly, she tells Mr. Bennet that "I wish you had been there, my dear, to have given [Mr. Darcy] one of your set-downs."
Anyways, back to grading exams... ;(
-Jean